the central dogma Flashcards
this help to break into amino acids
digestive enzymes
(amylase, protease, lipase,lactase, sucrase, maltase)
where do the amino acids enter after it has broken down by the digestive enzymes
bloodstream through the interior lining of the small intestine
and into the cells, where RNA molecules transcribed from genes guide their assembly into new proteins
nonessential -
conditionally essential -
essential -
nonessential - 5
body can produce on its own
no need to get from diet
Alanine
Asparagine
Aspartate
Glutamate
Serine
conditionally essential - 6
body can make them but if have illness or stress (metabolic disease) body may not produce enough
Arginine
Cysteine
Glutamine
Glycine
Proline
Tyrosine
essential -6
cannot be made by the body
get from food/ diet
Phenylalanine
Histidine
Isoleucine
Leucine
Lysine
Methionine
Threonine
Tryptophan
Valine
what is the structure of the amino acid
central carbon atom bonded
- hydrogen atom
- amino grp, NH2
- acid grp, COOH
- R group
*link via peptide bond
a protein that consists of one or more long chains of amino acids
polypeptides
shorter chains of amino acids
peptides
a protein’s three-dimensional shape
conformation
it is described the relationship between nucleic acids and proteins as a directional flow of information
called the central dogma
discovered by:
James Watson and Francis Crick
- their structure of DNA in 1953
differences and similarities of dna and rna
index card
The bases of an RNA sequence are complementary to those of one strand of the double helix
template strand
it is the non template strand of the DNA double helix
coding strand
*the coding region
- contains the sequence of codons
- carries the genetic info for translation
an enzyme that builds and RNA molecule
RNA polymerase
dna polymerase vs rna polymerase
index card
types of RNA (size)
- function
messenger RNA (500 - 4,500)
- encodes aa sequences
ribosomal RNA (100 - 300)
- associates w proteins = form ribosomes
- support and catalyze protein synthesis
translate RNA (75 - 80)
- transport specific aa to the ribosomes for protein synthesis
where does the rRNA found
in the ribosomes
“cell’s protein making machine”
-catalyze formation of peptide bonds between amino acids
ribosomes structure
large subunit (3 molecule)
- aka in eukaryotes: 60S subunits
- 5347 rna base
-47 proteins
- catalyze the formation of peptide bonds btwn aa
small subunit (1molecule)
- aka if in eukaryotes: 40S subunit (svedberg unit)
- 1869 rna base
- 32 proteins
- responsible for reading the mRNA during translation
-ensure that correct tRNA pairs with mRNA codons
*the ribosomes have 2 separate subunits in cytoplasm but they join at the site of the chain initiation
tRNA structure
index card
- tRNAs will bring in more amino acids to the dna
- connect one by one = form chain until stop signal
it is the protein that help control which gene to turn on or off
transcription factors
has a specific areas of thhe transcription factors called the binding domains
what are the different type of domains
helix-turn-helix:
twisted spiral, followed by a bend, and then another spiral.
zinc fingers:
resemble a “finger” that grabs the DNA, and they often need zinc (a metal) to hold their shape.
leucine zippers:
look like a zipper, with leucine (an amino acid) acting like the teeth of the zipper that help the transcription factor hold onto the DNA
steps of transcription
initiation:
rna polymerase attach to dna at the promoter
starts unwinding the DNA strand so it can read the gene
*promoter serves as the starting point
elongation:
RNA polymerase moves along the DNA strand
reading its sequence and building an RNA strand by adding complementary RNA bases (A, U, C, G
termination:
RNA polymerase reaches the terminator sequence (a “stop” signal) = stops transcription
made RNA is released, and RNA polymerase detaches from the DNA
help RNA polymerase find where to start on the DNA
transcription factors
flow of RNA processing
transcription:
cell makes a rough copy (pre-mRNA) of the DNA strand
copy includes everything - both the important parts (exons) and the unnecessary parts (introns)
modification:
cap” at the front end (5’ end) - like putting a protective cover on the beginning
“tail” at the back end (3’ end) made of many A’s - like adding a protective backing
splicing:
mRNA
cuts out introns
keeps exons
joins exons tgt
enzymes proofread the remaining RNA
final product:
mature mRNA
moves out the nucleus into the cytoplasm
- can be used to make proteins
what are the 4 genetic code
- the code is triplet
dna & rna uses 3-letter code called codon - the code does not overlap
code is read straight through in groups of three, without overlap
example: AUGCCCAAG is read as AUG-CCC-AAG (like reading word-by-word)
3.the code includes control
start” and “stop” signals built into the code
stop: UGA, UAA, and UAG
start: AUG
4.the code is same in all species
all living things (from bacteria to humans) use the same genetic code
different three-letter combinations can code for the same amino acid (synonymous codons)
what is the minimum no. of bases in a codon
3
how many does the genetic code cld specify 20 amino acids
64 different three-letter combinations to specify 20 amino acids
codons that termed different amino acids
nonsynonymous codons
different codon that specify the same amino acids
synonymous codons
the first amino acids in the protein chain
Met, methionine
terminating translation
ppt slide
where does translation take place
on free ribosomes in the cytoplasm
associated with the endoplasmic reticulum - make and transport proteins
after protein is made, how many times does the protein fold into
one or more conformations
- it folds to the right shape to function properly
it stabilize partially folded regions in their correct form, and prevent a protein from getting “stuck” in a useless intermediate form
chaperone proteins
- help guide folding process, fold into correct shapes and don’t get stuck in the middle of folding
what happens when a protein is folded incorrectly (misfolded)
a system called unfolded protein response kicks in
slow or stops the protein synthesis
while increasing the production of more chaperone proteins and other folding proteins to fix the problem.
it is when the misfolded proteins are sent out of the ER back into the cytoplasm, where they are “tagged” with yet another protein
ubiquitin
- If a protein gets one ubiquitin tag, it might be able to unfold and refold correctly.
what happens to the misfolded protein bearing
one ubiquitin tag:
more than one ubiquitin tag:
one ubiquitin tag:
straighten and refold correctly
more than one ubiquitin tag:
taken to another cellular machine called a proteasome
whr it breaks down into peptides to amino acids = reuse
what are the two ways that the proteins misfold
mutation:
change the aa sequences
alters attractions and repulsions
having more than one conformation:
proteins fold into more than 1 shape =
cant work properly
cause problems
what are the type of disease when proteins misfold and cant do their jobs properly
Alzheimer disease
Familial amyotrophic lateral sclerosis
frontotemporal dementia
Heredity ATTR amyloidosis
Parkinson disease
Lewy body dementia
PKU
Prion disease
what happens when one conformation becomes “infectious”
it converts molecules with other conformations into more copies of itself
- basically cause other proteins of the same kind to fold into this harmful shape. It’s like a bad influence that makes healthy proteins change into a harmful form.
this is called the “infectious proteins”
prion disease
- subgrp of protein misfolding
sheep > scrapie
proteinaceous infectious agents
proteins that can misfold and cause other proteins to misfold in a harmful way, leading to serious diseases.
prions
what is the first step in dna replication
unzip the dna
helicase breaks the hydrogen bonds of the bases into 2 strands
it attaches the primers to single strand
primase
function of dna polymerase
can only add new nucleotides in the 5’ to 3’ direction
what are the fragments called in the lagging strand
okazaki fragments
hence need ligase to connect those together
functions of proteins
blood clotting
muscle contractions
antibodies/ immunoglobulins
hair/ skin/ connective tissue
enzymes- important for biochemical functions
where do these process occur in the cell
replication:
transcription:
translation:
replication: nucleus (“S” phase)
transcription: nucleus
translation: cytoplasm (ribosomes)
this RNA encodes amino acid sequence
mRNA
this RNA associates with proteins to form ribosomes, which structurally support and catalyze protein synthesis
rRNA
this RNA transport specific amino acids to the ribosomes for protein synthesis
tRNA
when do the large and small subunit come together
both come tgt during translation to form a complete ribosome
it is a sequence that binds a complementary mRNA codon
anticodon
what is the function of the transcription factor
binds DNA at certain sequence
initiates transcription of specific site on chromosomes
*essential in initiation and regulation
it provides binding site for transcription factors and rna polymerase
promoters
this is the first transcription factor and a binding protein that recognizes the TATA regions and bind to DNA
TATA binding protein
what happens after rna polymerase is attached to the promoter
rna polymerase will unwind small portion of dna
directionality in
transcription:
synthesis:
transcription:
3’ to 5’ on a dna template strand
synthesis:
synthesis of mRNA in a 5’ to 3’ direction
what are the modifications made in the pre-mRNA
addition of the
5’ mRNA cap - modified guanine
helps protect RNA
help ribosomes recognize mRNA
3’ poly A tail - abt 200 adenine
stability
afterwards it will undergo splicing (spliceosomes)
remove the non coding regions, introns and combine coding regions, exons
it will then exit out of the nucleus to find ribosomes to undergo translation
what type of energy is used in the translation process
ATP:
initiation
GTP:
elongation
termination
one example of quaternary structure of a protein
hemoglobin
this protein stabilize partially folded regions in their correct form and prevent a protein from getting stuck in a useless intermediate form
chaperone
CTFR protein
The CFTR protein is like a little gate that controls salt and water flow in our cells. This helps keep mucus thin, so it can clear out easily, especially in the lungs.
Chaperone proteins are like helpers that make sure CFTR folds into the right shape so it can work properly. If CFTR doesn’t fold right, it can’t reach the cell’s surface, leading to thick mucus, which causes problems in conditions like cystic fibrosis.
